Speaking for neither his current boss, President George W. Bush - nor his future one, President-elect Barack Obama - Gates told top lawmakers in a New Year's Eve letter that the Pentagon would need nearly $70 billion more to supplement the $66 billion approved last year.
"This estimate is my personal assessment and does not reflect the position of the Bush administration or the incoming Obama administration," Gates said.
The estimate would cover Pentagon operations in Iraq and Afghanistan, as well as other elements of the global war on terror. An official request for war funding is coming after a review by the Obama administration, Gates said.
In the letter, sent to the chairmen of the House and Senate panels overseeing the war, Gates said that Congress should expect that the Obama administration "will conduct a fresh review of these matters and provide an updated and more authoritative proposal early next year."
Gates also said the estimate doesn't account for a proposed increase in the tempo of operations in Afghanistan.
Congress provided about $188 billion for the global war on terror in the 2008, according to the Congressional Research Service, as a surge in Iraq operations helped bring greater stability to the troubled nation. Obama has promised to bring down war costs as he works to remove most U.S. combat troops.
All told, CRS says, Congress has approved $864 billion for the overseas wars and other programs related to the battle against terrorism since Sept. 11, 2001. Such funding includes military operations, base security, reconstruction, foreign aid, embassy costs and veterans' health care.